Tornado 3.0 新特性¶

Mar 29, 2013¶

Highlights¶

  • The callback argument to many asynchronous methods is nowoptional, and these methods return a Future. The tornado.genmodule now understands Futures, and these methods can be useddirectly without a gen.Task wrapper.
  • New function IOLoop.current returns the IOLoop that is runningon the current thread (as opposed to IOLoop.instance, whichreturns a specific thread’s (usually the main thread’s) IOLoop.
  • New class tornado.netutil.Resolver provides an asynchronousinterface to DNS resolution. The default implementation is stillblocking, but non-blocking implementations are available using oneof three optional dependencies: ThreadedResolverusing the concurrent.futures thread pool,tornado.platform.caresresolver.CaresResolver using the pycareslibrary, or tornado.platform.twisted.TwistedResolver using twisted
  • Tornado’s logging is now less noisy, and it no longer goes directlyto the root logger, allowing for finer-grained configuration.
  • New class tornado.process.Subprocess wraps subprocess.Popen withPipeIOStream access to the child’s file descriptors.
  • IOLoop now has a static configuremethod like the one on AsyncHTTPClient, which can be used toselect an IOLoop implementation other than the default.
  • IOLoop can now optionally use a monotonic clock if available(see below for more details).

Backwards-incompatible changes¶

  • Python 2.5 is no longer supported. Python 3 is now supported in a singlecodebase instead of using 2to3
  • The tornado.database module has been removed. It is now availableas a separate package, torndb
  • Functions that take an io_loop parameter now default toIOLoop.current() instead of IOLoop.instance().
  • Empty HTTP request arguments are no longer ignored. This applies toHTTPRequest.arguments and RequestHandler.get_argument[s]in WSGI and non-WSGI modes.
  • On Python 3, tornado.escape.json_encode no longer accepts byte strings.
  • On Python 3, the get_authenticated_user methods in tornado.authnow return character strings instead of byte strings.
  • tornado.netutil.TCPServer has moved to its own module,tornado.tcpserver.
  • The Tornado test suite now requires unittest2 when run on Python 2.6.
  • tornado.options.options is no longer a subclass of dict; attribute-styleaccess is now required.

Detailed changes by module¶

Multiple modules¶

  • Tornado no longer logs to the root logger. Details on the new loggingscheme can be found under the tornado.log module. Note that in somecases this will require that you add an explicit logging configurationin order to see any output (perhaps just calling logging.basicConfig()),although both IOLoop.start() and tornado.options.parse_command_linewill do this for you.
  • On python 3.2+, methods that take an ssl_options argument (onSSLIOStream, TCPServer, and HTTPServer) now accept either adictionary of options or an ssl.SSLContext object.
  • New optional dependency on concurrent.futures to provide better supportfor working with threads. concurrent.futures is in the standard libraryfor Python 3.2+, and can be installed on older versions withpip install futures.

tornado.autoreload¶

  • tornado.autoreload is now more reliable when there are errors at importtime.
  • Calling tornado.autoreload.start (or creating an Application withdebug=True) twice on the same IOLoop now does nothing (instead ofcreating multiple periodic callbacks). Starting autoreload onmore than one IOLoop in the same process now logs a warning.
  • Scripts run by autoreload no longer inherit future importsused by Tornado.

tornado.auth¶

  • On Python 3, the get_authenticated_user method family now returnscharacter strings instead of byte strings.
  • Asynchronous methods defined in tornado.auth now return aFuture, and their callback argument is optional. TheFuture interface is preferred as it offers better error handling(the previous interface just logged a warning and returned None).
  • The tornado.auth mixin classes now define a methodget_auth_http_client, which can be overridden to use a non-defaultAsyncHTTPClient instance (e.g. to use a different IOLoop)
  • Subclasses of OAuthMixin are encouraged to overrideOAuthMixin._oauth_get_user_future instead of _oauth_get_user,although both methods are still supported.

tornado.concurrent¶

tornado.curl_httpclient¶

  • Preliminary support for tornado.curl_httpclient on Python 3. The latestofficial release of pycurl only supports Python 2, but Ubuntu has aport available in 12.10 (apt-get install python3-pycurl). This portcurrently has bugs that prevent it from handling arbitrary binary databut it should work for textual (utf8) resources.
  • Fix a crash with libcurl 7.29.0 if a curl object is created and closedwithout being used.

tornado.escape¶

  • On Python 3, json_encode no longer accepts byte strings.This mirrors the behavior of the underlying json module. Python 2 behavioris unchanged but should be faster.

tornado.gen¶

  • New decorator @gen.coroutine is available as an alternative to@gen.engine. It automatically returns aFuture, and within the function instead ofcalling a callback you return a value with raise
    gen.Return(value) (or simply return value in Python 3.3).
  • Generators may now yield Future objects.
  • Callbacks produced by gen.Callback and gen.Task are now automaticallystack-context-wrapped, to minimize the risk of context leaks when usedwith asynchronous functions that don’t do their own wrapping.
  • Fixed a memory leak involving generators, RequestHandler.flush,and clients closing connections while output is being written.
  • Yielding a large list no longer has quadratic performance.

tornado.httpclient¶

  • AsyncHTTPClient.fetch now returns a Future and its callback argumentis optional. When the future interface is used, any error will be raisedautomatically, as if HTTPResponse.rethrow was called.
  • AsyncHTTPClient.configure and all AsyncHTTPClient constructorsnow take a defaults keyword argument. This argument should be adictionary, and its values will be used in place of correspondingattributes of HTTPRequest that are not set.
  • All unset attributes of tornado.httpclient.HTTPRequest are nowNone. The default values of some attributes(connect_timeout, request_timeout, follow_redirects,max_redirects, use_gzip, proxy_password,allow_nonstandard_methods, and validate_cert have been movedfrom HTTPRequest to the clientimplementations.
  • The max_clients argument to AsyncHTTPClient is now a keyword-onlyargument.
  • Keyword arguments to AsyncHTTPClient.configure are no longer usedwhen instantiating an implementation subclass directly.
  • Secondary AsyncHTTPClient callbacks (streaming_callback,header_callback, and prepare_curl_callback) now respectStackContext.

tornado.httpserver¶

  • HTTPServer no longer logs an error when it is unable to read a secondrequest from an HTTP 1.1 keep-alive connection.
  • HTTPServer now takes a protocol keyword argument which can be setto https if the server is behind an SSL-decoding proxy that does notset any supported X-headers.
  • tornado.httpserver.HTTPConnection now has a set_close_callbackmethod that should be used instead of reaching into its streamattribute.
  • Empty HTTP request arguments are no longer ignored. This applies toHTTPRequest.arguments and RequestHandler.get_argument[s]in WSGI and non-WSGI modes.

tornado.ioloop¶

  • New function IOLoop.current returns the IOLoop that is runningon the current thread (as opposed to IOLoop.instance, which returns aspecific thread’s (usually the main thread’s) IOLoop).
  • New method IOLoop.add_future to run a callback on the IOLoop whenan asynchronous Future finishes.
  • IOLoop now has a static configuremethod like the one on AsyncHTTPClient, which can be used toselect an IOLoop implementation other than the default.
  • The IOLoop poller implementations (select, epoll, kqueue)are now available as distinct subclasses of IOLoop. InstantiatingIOLoop will continue to automatically choose the best availableimplementation.
  • The IOLoop constructor has a new keyword argument time_func,which can be used to set the time function used when scheduling callbacks.This is most useful with the time.monotonic function, introducedin Python 3.3 and backported to older versions via the monotimemodule. Using a monotonic clock here avoids problems when the systemclock is changed.
  • New function IOLoop.time returns the current time according to theIOLoop. To use the new monotonic clock functionality, all calls toIOLoop.add_timeout must be either pass a datetime.timedelta ora time relative to IOLoop.time, not time.time. (time.time willcontinue to work only as long as the IOLoop’s time_func argumentis not used).
  • New convenience method IOLoop.run_sync can be used to start an IOLoopjust long enough to run a single coroutine.
  • New method IOLoop.add_callback_from_signal is safe to use in a signalhandler (the regular add_callback method may deadlock).
  • IOLoop now uses signal.set_wakeup_fd where available (Python 2.6+on Unix) to avoid a race condition that could result in Python signalhandlers being delayed.
  • Method IOLoop.running() has been removed.
  • IOLoop has been refactored to better support subclassing.
  • IOLoop.add_callback and add_callback_from_signal now takeargs, *kwargs to pass along to the callback.

tornado.iostream¶

  • IOStream.connect now has an optional server_hostname argumentwhich will be used for SSL certificate validation when applicable.Additionally, when supported (on Python 3.2+), this hostnamewill be sent via SNI (and this is supported by tornado.simple_httpclient)
  • Much of IOStream has been refactored into a separate classBaseIOStream.
  • New class tornado.iostream.PipeIOStream provides the IOStreaminterface on pipe file descriptors.
  • IOStream now raises a new exceptiontornado.iostream.StreamClosedError when you attempt to read orwrite after the stream has been closed (by either side).
  • IOStream now simply closes the connection when it gets anECONNRESET error, rather than logging it as an error.
  • IOStream.error no longer picks up unrelated exceptions.
  • BaseIOStream.close now has an exc_info argument (similar to theone used in the logging module) that can be used to set the stream’serror attribute when closing it.
  • BaseIOStream.read_until_close now works correctly when it is calledwhile there is buffered data.
  • Fixed a major performance regression when run on PyPy (introduced inTornado 2.3).

tornado.log¶

tornado.netutil¶

tornado.options¶

tornado.platform.caresresolver¶

  • New module containing an asynchronous implementation of the Resolverinterface, using the pycares library.

tornado.platform.twisted¶

tornado.process¶

tornado.simple_httpclient¶

  • SimpleAsyncHTTPClient now takes a resolver keyword argument(which may be passed to either the constructor or configure), to allow it to use the new non-blockingtornado.netutil.Resolver.
  • When following redirects, SimpleAsyncHTTPClient now treats a 302response code the same as a 303. This is contrary to the HTTP specbut consistent with all browsers and other major HTTP clients(including CurlAsyncHTTPClient).
  • The behavior of header_callback with SimpleAsyncHTTPClient haschanged and is now the same as that of CurlAsyncHTTPClient. Theheader callback now receives the first line of the response (e.g.HTTP/1.0 200 OK) and the final empty line.
  • tornado.simple_httpclient now accepts responses with a 304status code that include a Content-Length header.
  • Fixed a bug in which SimpleAsyncHTTPClient callbacks were being run in theclient’s stack_context.

tornado.stack_context¶

  • stack_context.wrap now runs the wrapped callback in a more consistentenvironment by recreating contexts even if they already exist on thestack.
  • Fixed a bug in which stack contexts could leak from one callbackchain to another.
  • Yield statements inside a with statement can cause stackcontexts to become inconsistent; an exception will now be raisedwhen this case is detected.

tornado.template¶

  • Errors while rendering templates no longer log the generated code,since the enhanced stack traces (from version 2.1) should make thisunnecessary.
  • The {% apply %} directive now works properly with functions that returnboth unicode strings and byte strings (previously only byte strings weresupported).
  • Code in templates is no longer affected by Tornado’s future imports(which previously included absolute_import and division).

tornado.testing¶

tornado.util¶

  • tornado.util.b (which was only intended for internal use) is gone.

tornado.web¶

  • RequestHandler.set_header now overwrites previous header valuescase-insensitively.
  • tornado.web.RequestHandler has new attributes path_args andpath_kwargs, which contain the positional and keyword argumentsthat are passed to the get/post/etc method. These attributesare set before those methods are called, so they are available duringprepare()
  • tornado.web.ErrorHandler no longer requires XSRF tokens on POSTrequests, so posts to an unknown url will always return 404 instead ofcomplaining about XSRF tokens.
  • Several methods related to HTTP status codes now take a reason keywordargument to specify an alternate “reason” string (i.e. the “Not Found” in“HTTP/1.1 404 Not Found”). It is now possible to set status codes otherthan those defined in the spec, as long as a reason string is given.
  • The Date HTTP header is now set by default on all responses.
  • Etag/If-None-Match requests now work with StaticFileHandler.
  • StaticFileHandler no longer sets Cache-Control: public unnecessarily.
  • When gzip is enabled in a tornado.web.Application, appropriateVary: Accept-Encoding headers are now sent.
  • It is no longer necessary to pass all handlers for a host in a singleApplication.add_handlers call. Now the request will be matchedagainst the handlers for any host_pattern that includes the request’sHost header.

tornado.websocket¶

原文:

https://tornado-zh-cn.readthedocs.io/zh_CN/latest/releases/v3.0.0.html